Light weight golf clubs are well known in the art and have gained a measure of popularity. The light weight golf clubs have a number of advantages including being lighter to carry and having desirable flexional characteristics. The light weight golf shafts of the prior art are more easily accelerated during swinging and better absorb the vibrations caused by striking the ball. However the light weight golf clubs of the prior art also have some disadvantages. One disadvantage of the prior art light weight golf clubs is that their light weight gives them a feel during swinging that is different from the traditional steel shafted golf clubs. The instant invention overcomes this disadvantage as set forth below.
Another disadvantage of the lightweight golf clubs is that their construction often leaves the tip end of the golf shaft opposite the handle portion weak. As a result, this is a common point of fracture in the prior art light weight clubs. U.S. Pat. No. 5,820,483 to Preece et al is directed at solving this problem by including a plug in the weak end portion. This plug structurally strengthens the end of the shaft to be inserted into the golf head. U.S. Pat. No. 6,139,444 to Renard et al among other things strengthens the tip portion of a golf shaft by a stiffener. U.S. Pat. No. 4,836,545 to Pompa similarly provides a stiffener at the tip end of the golf shaft.
U.S. Pat. No. 5,984,803 to Chappell teaches redistributing the weight of the golf club from the hosel area to the head. U.S. Pat. No. 5,685,783 to Akatsuka has a light weight golf shaft of composite materials formed by a variety of layers. This prior art device also includes attachment of the shaft to the head by an internal joint member and discloses the possibility of a core member inside the shaft. U.S. Pat. No. 5,465,959 to Cheng is directed to a composite bent shaft for a golf club. This device also has a core and a link inside a composite material shaft.
None of the prior art devices addresses the same specific need of providing a feel similar to a typical steel shafted golf club in composite materials shafted golf clubs. The closest prior art that has core or plug structure fails to provide a variety of weighting plugs for the purpose of selectively providing different weights in golf shafts. Simply stated, the prior art fails to weight golf shafts in order to increase their swing weights. Furthermore, core or plug structure that may happen to provide weight to a golf shaft fails to do so in the variable and useful way that is provided by the instant invention.
The instant invention fulfills the need for a light weight golf club that provides a swing weight similar to that of a typical steel shafted golf club. This is provided by construction of the golf shaft as a non-metal or composite shaft with a weighting plug in a tip end opposite a handle portion of the golf shaft. Thus, a shaft, a golf club, or a set of shafts or clubs constructed in accordance with the present invention provides the advantages of light weight composite shafts while also providing the advantage of providing a feel during swinging similar to that experienced during swinging of typical steel shafted clubs.
Generally, applying the invention to the making of golf shafts and corresponding golf clubs comprises the steps of:
(a) providing a light weight golf shaft with a weighting plug selected from a plurality of weighting plugs having different weights,
(b) attaching a golf head to the golf shaft.
More specifically, the method includes the steps of weighting the plug and forming the plug and golf shaft into a one piece composite member.
The swing weight is made similar to that of steel shafted golf clubs by forming weighting plugs in a molding process by selectively adding higher density materials to the resin to be molded. By varying the quantity and composition of the higher density material, the weight of the weighting plug can be substantially infinitely adjustable within a predetermined range. In this way, a swing weight for a particular golf shaft or club can be selected. Likewise, the plug weights of a set of golf shafts or golf clubs can be selectively varied in a manner to increase the playability of the set. For example, the typically lighter clubs in a set can be constructed with heavier plugs so that all of the clubs in a set will have substantially the same swing weight.